Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended			6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2024	Mar. 31, 2023	Jul. 05, 2017
Basic earnings (loss) per common share:
Net income (loss) - basic	$ 21,479,000	$ (6,790,000)		$ 49,949,000	$ 9,988,000
Weighted shares outstanding - basic (in shares)	55,093	55,648		55,084	55,981
Basic earnings (loss) per common share (in dollars per share)	$ 0.39	$ (0.12)		$ 0.91	$ 0.18
Diluted earnings (loss) per common share:
Net income (loss) - basic	$ 21,479,000	$ (6,790,000)		$ 49,949,000	$ 9,988,000
Add: Convertible Notes expense, net of tax	2,415,000	0		5,074,000
Add: Convertible Notes expense, net of tax					(2,733,000)
Net income (loss) - diluted	$ 23,894,000	$ (6,790,000)		$ 55,023,000	$ 7,255,000
Weighted shares outstanding - basic (in shares)	55,093	55,648		55,084	55,981
Equity-based compensation awards - effect of dilution (in shares)	974	0		1,156	1,067
Convertible Notes - effect of dilution (in shares)	26,978	0		28,708	8,221
Weighted shares outstanding - diluted (in shares)	83,045	55,648		84,948	65,269
Diluted earnings (loss) per common share (in dollars per share)	$ 0.29	$ (0.12)		$ 0.65	$ 0.11
Potential common shares excluded from the calculation of diluted earnings (loss) per common share above (in shares)	1,676	32,935		1,673	21,669
Loss on extinguishment of debt			$ 3,500,000	$ 0	$ 3,545,000
2025 Convertible Notes
Diluted earnings (loss) per common share:
Loss on extinguishment of debt					5,400,000
2024 Convertible Notes | Senior Notes
Diluted earnings (loss) per common share:
Potential common shares excluded from the calculation of diluted earnings (loss) per common share above (in shares)	3,400
Loss on extinguishment of debt	$ 0	$ 0		$ 0	$ 8,935,000
Principle amount						$ 143,750,000
Weighted average shares				1,700
Conversion price, per share (in dollars per share)	$ 10.00			$ 10.00		$ 10.00
Equity-based compensation awards
Diluted earnings (loss) per common share:
Potential common shares excluded from the calculation of diluted earnings (loss) per common share above (in shares)	0	1,014		0	0
Convertible Notes
Diluted earnings (loss) per common share:
Potential common shares excluded from the calculation of diluted earnings (loss) per common share above (in shares)	0	30,417		0	20,141
Restricted stock
Diluted earnings (loss) per common share:
Potential common shares excluded from the calculation of diluted earnings (loss) per common share above (in shares)	1,676	1,504		1,673	1,528